Partial saponification of cellulose ester material



y 5, 1932- c. DREYFUS ET AL 1,866,153

PARTIAL SAPONIFICATION 0F CELLULOSE ESTER MATERIAL Filed Oct. 22, 1929 WATER 3% Na OH (DM PENSATO R 8 INVENTORS CAMILLE DREYFUS HERBERT/PLATT 5- Na OH Patented July 5, 1932 UNITED STATES PATENT OFFICE CAMILLE DREYFUS, OF NEW YORK, N. Y.

MARYLAND, ASSIGNORS TO CELANESE CORPORATION OF AMERICA, COBPORA-i TION or DELAWARE AND HERBERT PLATT, OF CUIML'BELAND,

PARTIAL SAPONIFICATION OF CELLULOSE ESTER MATERIAL Application filed October 22, 1929. Serial No. 401,578.

This invention relates to the treatment of textile material containin organic esters of cellulose, whereby the sa e ironing point of the same is improved and other desirable properties are imparted thereto;

An object of our invention is to increase the safe ironing point of textile materials containing organic esters of cellulose by thepartial saponification of the same in a continuous manner. Other objects of our invention will appear from the following detailed description.

The partial saponification of organic esters of cellulose textile material to Increase the safe ironing point of the same is attended with many difliculties owing to the fact that unless the same be carried out under certain definite conditions, 'the saponification proceeds unevenly and level dyeing of the textile material is not possible. Furthermore for reasons of economy, it is desirable to carry out thepartial saponification in a continuous manner.

We have found that if an aqueous solution of an alkaline material-is applied to a moving fabric containing organic esters of cellulose yarn, and then a weaker alkaline solution is applied, and then the fabric is washed, all operations proceeding continuously, excellent results are obtained. The organic ester of cellulose filaments of the fibre is intensely saponified on the surface thereof in an even manner, with the result that the safe ironing point of the same is raised and the fabric is capable of being dyed level. Moreover, by this process, the fabric is partially saponified and scoured at the same time, thus avoiding the necessity of .scouring as a separate operation.

In accordance with our invention, we partially saponify fabric containing yarns or filaments of organic esters of cellulose by continuously applying thereto a comparatively strong solution of an alkaline material, then continuously applying a weaker alkaline solution, and then continuously washing with water in a series of washers so as to wash out all the alkaline-material and metallic salts formed by the saponification.

The fabric to be treated may contain yarns ters of cellulose but may also contain other fibres such as cotton or reconstituted cellulose.

The alkaline material applied in the saponifying solutions may be any suitable one such as sodium hydroxide or potassium hydroxide, which may be replaced in whole or inpart by alkaline salts such as the carbonate of sodium or potassium, the silicate ofsodium or' potassium, or the sulphide of sodium or potassium.

As stated the fabric is first treated with an alkaline solution of comparatively eater concentration. This solution is pre erably of anialkalinity corresponding to a concentration of 4 to 7% of sodium hydroxide and is preferably at room temperatures. It may be applied to the fabric in any suitable manner such as on a pad, by a jig or in a box.

After the stronger alkaline solution has been applied, a weaker alkaline solution is then applied. This alkaline solution is of a concentration corresponding to 2 to 4% of caustic soda and is preferably at a temperature of to 85 C.

After the application of the weaker alkaline solution, the fabric is thoroughly washed in water, preferably of a temperature of 70 to 85 C'., in a series of washers which may be in the form of boxes, jigs, etc. During the washing, the fabric may be subjected to an intermediate spray of water, and excess water may be expressed from the fabric by means of nips before the same proceeds to the next washing bath.

The fabric may be first dyed and then subjected to the partial saponification process, or it may be dyed subsequent to such process.

The fabric after having been treated in this manner contains fibres of cellulose esters that are intensely saponified on the surface thereof. The safe ironing point of the fabric is materially increased and the fabric is capable of level dyeing.

In order further to illustrate our invention, reference is had to the accompanying drawing, wherein Y Figure 2 is a diagrammatic view of a paratus for carrylng out a second form 0 our invention.

Referring to Figure 1, an example of car- Eying out this invention will be described. he fabric 1 consisting wholly of yarnsof cellulose acetate is passed from the roll 2 into the jig 3 where it is subjected to an aquemay move verticall washing ous bath containing from 5 to 6% of caustic soda. The fabric then passes around the rolls 4 to the jig 5 which contains an aqueous solution of 3% caustic soda, which solution is at C. The'fabric then proceeds around the roll 6 to the jig 7 which contains water at 80 C. and where itis subjected to its first treatment. In passing from the jig 7, the fabric may be subjected to a spray 0 water issuing from the spray pipe 8, and then passes around the rolls 9 to the washing jig 10 which contains water at 80 C. The fabric may then be subjected to a second spray from pipe 11 and then passes around the rolls 12 to the jig 13 .where it is given its final washing with water at 80 C'. and is then passed over the roll 14 and then batched, the arrangement bein that the rate of travel of the fabric through the baths is substantially uniform. The fabric thus treated is partlally saponified and scoured and may then be given any subsequent finishing treatment such as dyeing, printing, etc.

Referring to Figure 2, another example of carryin out our invention will be described. The fa ric 1 consisting wholly of cellulose acetate am is assed from the roll 20 to the pad er 21 w 'ch contains a caustic soda solution of 5% concentration at room temperature. The fabric is caused to pass under the surface of thecaustic soda solution by means of the roll 22 and then passes between the padding rolls 23 to the compensator 24. The compensator 24 comprises the rolls 25, 26 and 27. The roll 26 is mounted so that it in order to take up slack mm the compensator 24, the fabric passes to the box 28 containing caustic soda solution of 3% concentration at C. From the box 28 the fabric passes between the nip rolls 29. which removes the excess of the caustic soda solution contained on the fabric. The fabric then passes to the first washing box 30 which contains running water at 85 C. and on leaving the same may be subjected to a spray of water issuing from the spray pipe 31. T e fabric is then passed between't e nip rollers 32 to remove excess of washing water and then passes to the second washing box 33 containing running water at 85C. On leaving the washing box 33, the fabric may be s rayed with water from spray pipe 34, asse between ni rolls 35, and then rolled up as roll 36. T 's fabric on the fabric 1.

has been simultaneously partially saponified and scoured and may be subjected to any finishing treatment desired.

It is to be understood that the foregoing detailed description is given merely by way 0 illustration, and that many variations may be made therein without departing from the spirit of our invention.

Having described our invention, what we claim and desire to secure by Letters Patent 1s:

1. Method of partially saponifying fabric containing organic esters of cellulose com prising applying an alkaline solution of relatively greater concentration to the fabric and then applying analkaline solution of less concentration, the operations being performed while the fabric is moving continuously. i 2. Method of partially saponifying fabric containing cellulose acetate com rising applying an alkaline solution 0 relatively greater concentration to the fabric and then applying an alkaline solution of less concentration, the operations being performed while the fabric is moving continuously.-

3. Method of partially saponi g fabric containing organic esters of ce ulose comprising applying an alkaline solution of relatively greater concentration to the fabric, then applying an alkaline solution of less concentration, and then washing, the operations being performed while the fabric is movin continuously. 4. ethod of upartially saponifying fabric containing cell ose acetate com plying an alkaline solution 0 relative y greater concentration to the fabric, then applying an alkaline solution of less concentration, and then washing, the operations bensmg a ing performed while the fabric is moving continuously.

5. Method of partially saponifying fabric containing orgamc esters of cellulose continuously comprising applying thereto an alkaline solution corres onding to a solution of sodium hydroxide o substantially 4 to 7% concentration, then applying an alkaline solution correspondin to a solution of sodium hydroxide of substantially 2 to 4% concentration and then washing with water,

the operations being performed while the fabricismovin continuously.

6. Method 0 partially saponifying fabric containing cellulose acetate continuously comprising applying thereto an alkaline solu tion correspondlng to a solution of sodium hydroxide of substantially 4 to 7% concentration, thenapplying an alkaline solution corres ondin to a solution of sodium hydroxi e of su ntially 2 to 4% concentration and then washing with water, the operations being performed while the fabricvis thod of partially fabric .movin continuously.

comprising organic esters of cellulose continuously comprising applying thereto an alkaline solution corresponding to a solution of sodium hydroxide of substantially 4 to 7% concentration at substantially room temperatures, then applying an alkaline solution corresponding to a solution of sodium hydroxide of substantially 2 to 4% concentration at substantially to (1., and then washing with water at temperatures of substantially 70 to 85 C., the operations being performed while the fabric is moving continuously.

8. Method of partially saponifying fabric comprising cellulose acetate continuously comprising applying thereto an alkaline solution corresponding to a solution of sodium hydroxide of substantially 4 to 7% concentration at substantially room-temperatures, then applying an alkaline solution corresponding to a. solution of sodium hydroxide of substantially 2 to 4% concentration at substantially 70 to 85 0., and then washing with water at temperatures of substantially 70 to 85 0., the operations being performed while the fabric is moving continuously.

In testimony whereof, we have hereunto subscribed our names.

CAMILLE DREYFUS. HERBERT PLATT. 

